Yesterday at New York International Auto Show, Porsche announced a six-year partnership with Microsoft's Turn 10 Studios. In case you're unaware, Turn 10 Studios is the developer of the critically acclaimed Forza series. So this deal obviously means Porsche cars in Forza games.
And let's start by having the new "Porsche Car Pack" DLC for Forza Horizon 3, which adds seven Porsche cars (including the classical 1960 768 RS60 and the modern 911 GT3 RS) to the game. You can download it from the Microsoft store.

They also launched a trailer:

That's not all. An open-to-all E-Sports tournament for Forza Horizon 3, sponsored by Porsche, is also announced. The tournament is called "Forza Racing Championship Season 3: The Porsche Cup". It'll begin on May 1. If you're interested, you can sign-up here.